Dielectric properties and conductivity studies of some tetradentate cobalt(II), nickel(II), and copper(II) Schiff base complexes (original) (raw)
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One of the most interesting areas of research is that of electrically conducting organometallic polymers . The method of choice for producing conducting organometallic polymers involves complexing transition metals with conjugated bridging ligands. The ability to alter the oxidation state of the metal ion, and thus the charge density along the polymer backbone, provides an alternative route to charge carrier creation as opposed to redox doping. Polyamides and their poly chelates have σ values at 298K of about 10 -6 -10 -11 ohm-1 cm-1. The temperature dependant σ has a typical break point at 410-450 K with lower ΔE values at higher temperature. Marcu and Dima have prepared the polymers of dimethyl-4,4'-[p-phenylene-bis (methylidene nitrilo)] disalicylate with Co(II), Ni(II) and Cu(II) in DMF and reported that these polymers are heat stable, semi conducting in nature. Semiconducting properties of poly chelates 2, 5-dihydroxy phthaldehyde and series of di and tetra amino compounds and monomeric Schiff bases and their chelates have been reported . Electrical conducting properties of metal chelates of azines have been reported . Coordination polymers of Cu(II) and Ni(II) with ethylene diamine tetrahalato and tetra thioazalatotetrathio flavane were prepared and their electrical conductivity has been studied . In view of the above discussion, the present work deals with electrical conductivity studies on Co(II), Cu(II) and Ni(II) complexes of Schiff base derived from Riluzole with different aldehydes.
One of the most interesting areas of research is that of electrically conducting organometallic polymers . The method of choice for producing conducting organometallic polymers involves complexing transition metals with conjugated bridging ligands. The ability to alter the oxidation state of the metal ion, and thus the charge density along the polymer backbone, provides an alternative route to charge carrier creation as opposed to redox doping. Polyamides and their poly chelates have σ values at 298K of about 10 -6 -10 -11 ohm-1 cm-1. The temperature dependant σ has a typical break point at 410-450 K with lower ΔE values at higher temperature. Marcu and Dima have prepared the polymers of dimethyl-4,4'-[p-phenylene-bis (methylidene nitrilo)] disalicylate with Co(II), Ni(II) and Cu(II) in DMF and reported that these polymers are heat stable, semi conducting in nature. Semiconducting properties of poly chelates 2, 5-dihydroxy phthaldehyde and series of di and tetra amino compounds and monomeric Schiff bases and their chelates have been reported . Electrical conducting properties of metal chelates of azines have been reported . Coordination polymers of Cu(II) and Ni(II) with ethylene diamine tetrahalato and tetra thioazalatotetrathio flavane were prepared and their electrical conductivity has been studied . In view of the above discussion, the present work deals with electrical conductivity studies on Co(II), Cu(II) and Ni(II) complexes of Schiff base derived from Riluzole with different aldehydes.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2005
A bright green CoCu(PMP)(OH) 2 (H 2 O) 2 complex was synthesized. Its structure was elucidated and characterized by different spectroscopic techniques. Both cobalt and copper atoms attain tetrahedral geometry. The complex was investigated by the dielectric relaxation spectroscopy. The dielectric parameters are discussed in terms of temperature and frequency changes. The conductivity of the complex decreased as the temperature increased in the temperature range 30-100 • C, while above this temperature range stepwise increase in the conductivity was observed.
International Journal for Research in Applied Science & Engineering Technology (IJRASET), 2023
The dielectric behaviour and molecular structure of metal complexes Cu(II),Ni(II) and UO 2 ((VI) of the ligand oxaloanilic acid hydrazine have been investigated using Time Domain Reflectometry (TDR) technique in the frequency range 10 MHz to 10GHz. Cole-Davidson model has been applied for fitting the complex permittivity spectra [ ε * (ω)]. The parameters ε s-the static permittivity, τ-the dielectric relaxation time are evaluated at different temperatures from 288 0 K to 333 0 K and are discussed in respect of their molecular structural behaviours. The thermodynamic parameters, such as ΔH *-molar enthalpy, ΔS *-the molar entropy are obtained using Eyring.s rate equation. In the light of such data the possible structures of the present complexes are discussed.
Bulletin of the Chemical Society of Ethiopia, 2014
Metal complexes of VO(IV), Zr(IV), Th(IV) and UO2(VI) with Schiff base ligands derived from 4-nitrobenzoylhydrazide with 2-hydroxy-5-methylacetophenone (H2L 1) or 2-hydroxy-5-chloroacetophenone (H2L 2) have been prepared. All the complexes have been characterized on the basis of elemental analyses, magnetic susceptibility measurement, electronic and IR spectra and thermogravimetric analysis. The IR spectral data suggested that the ligands behave as dibasic tridentate moiety towards the central metal ion coordinating through phenolic oxygen, enolic oxygen and azomethine nitrogen atoms. The elemental analyses show a 1:1 metal:ligand stoichiometry for all the complexes except Th(IV) which has 1:2 stoichiometry. The thermal analysis evidenced that thermal transformations of complexes are processes according to TG curves including dehydration, thermolysis and oxidative degradation of Schiff base. The final product of decomposition is the most stable metallic oxide. The kinetic analysis of the thermogravimetric data was performed by using the Coats-Redfern method. Solid state electrical conductivity of the complexes has been measured in their compressed pellet form over a 310-413 K temperature range. All the complexes show semiconducting behavior as their conductivity increases with increasing temperature and a function of ionic size. All the complexes along with ligands were also screened for their antibacterial and antifungal activities.
Transition Metal Chemistry, 1990
A series of metal complexes with three new tetradentate Schiff bases derived from benzoin and benzil withc-toluidine and benzil with diaminoethane have been prepared and characterised by physical and chemical methods. The modes of bonding of the ligands with the metal ions have been proposed. Electronic spectra and room temperature magnetic moment values suggest octahedral geometry for the CoII and NiII complexes, whereas the HgII and CdII complexes have tetrahedral geometry. The CuII complexes are square planar. Apart from the complexes of the Schiff bases derived from benzoin, all the other complexes have high molar conductance values suggesting them to be electrolytes. The complexes have been screened against some fungal pathogens.
Journal of Electronic Materials, 2019
In this study, Co(II) and Pd(II) complexes of a Schiff base ligand, methyl-2-((5bromo-2-hydroxybenzylidene)amino)-6-phenyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate (L), were prepared and characterized used through FT-IR, UV-Vis., microanalyses, magnetic susceptibility, 1 H-NMR, 13 C-NMR, mass and thermogravimetric analyses. Optical transition and band structure properties, extinction characteristics, refractive indices and ambient behaviors, dielectric and electric susceptibility characteristics of the ligand, Co(II) and Pd(II) complex compounds were investigated in detail. Moreover, the impacts of the two complexes on these parameters and features of the ligand were examined. The main finding of the study was that the Co(II) complex decreased the optical band gap of the ligand from 2.682 to 2.357 eV.
Transition Metal Chemistry, 1983
Complexes of cobalt(II) and copper(II) having the composition [ML(H2O)2] and of cadmium(II) and mercury(II) of the type [ML], where LH2 is the tetradentate ONNO donor Schiff base derived from benzoin and 1,2-diaminopropane, have been characterised by analysis, conductance, magnetic susceptibility, i.r. and electronic spectral studies. The cobalt(II) and copper(II) complexes are either octahedral or distortedoctahedral, and the cadmium(II) and mercury(II) complexes are tetrahedral. The thermal decompositions of the cobalt(II) and copper(II) complexes were studied by DTG and DTA techniques.
Electrical Conductivity Studies on Co(II), Cu(II), Ni(II) and Cd(II) Complexes of Azines
1-Phenyl-4-(2'-hydroxyphenyl-1-yl)di-imino azine, {1P-4-(2' HPDA)} 1, 4(2'-hydroxyphenyl-1-yl)di-imino azine, {1, 4-(2' HPDA)} are derived from benzophenone hydrozone with different aldehydes in presence of few drops of concentrated hydrochloric acid in alcoholic medium. Metal(II) complexes have been prepared by salts of CoCl 2 , CuCl 2 , NiCl 2 and CdCl 2 reacting with azine ligands dissolved in alcohol in the molar ratio of (1:2). The prepared complexes were characterized by using various physical methods viz. elemental, molar conductance, magnetic susceptibility, IR, NMR, XRD and UV-Visible. Conductivity of the powder samples were measured by two probe method. Measured electrical conductivities of Co(II), Cu(II), Ni(II) and Cd(II) complexes of azines are reported in this paper. It is found that at room temperature these complexes show insulator behavior. At higher temperature conductivity increases linearly, showing semi conducting behavior.
Dielectric properties of some cadmium and mercury amino alcohol complexes at low temperatures
Journal of the Serbian Chemical Society, 2002
The dielectric properties of some cadmium and mercury amino alcohol complexes were studied within the temperature range of 100-300 K at the frequencies of 100, 300 and 1000 kHz. The polarization mechanisms are suggested and the dependence of both e and tg d on both temperature and frequency are analyzed. The analysis of the data reveals semi-conducting features based mainly on the hopping mechanism.